Sea Level Rise

Climate is having a massive impact on the oceans.  Warmer air with increasing concentration of carbon dioxide is causing two main problems: sea level rise and ocean acidification.  For many people—especially those who live near coasts—their primary concern is in the indisputable fact that sea levels are rising around the world.  This is being caused by the warming effect of the atmosphere of ocean waters, which warming causes the total volume of the sea to expand.  Additionally, warmer temperatures around the globe are causing a net loss of land-based glaciers, allow more of this previously stored water to flow into the ocean.  Sea level rise is a big problem for cities located by coastline and homeowners with beachfront property.  We are providing some resources and references about sea level risk to help you understand your risk.  Unfortunately, while sea level rise is important, the impacts on our future well-being is dwarfed by the risks posed to the health of marine ecosystems by the other impact of climate change: ocean acidification.

MMM

Acidification, De-oxygenation and Extinctions

Click image to listen to Michael Krasny’s Forum interview with author Elizabeth Kolbert about her book “Earth’s Sixth Mass Extinction.”

Scientists have figured out that approximately 30% of all of mankind’s excess atmospheric CO₂ emissions — more than 1.5 trillion tons of CO₂ — has been absorbed by the oceans already. The effect of this carbonization is causing the ocean to become less alkaline, i.e. to have a lowering pH and correspondingly greater acidity. This is causing a fundamental change in the chemistry of the ocean from pole to pole, broadly called “ocean acidification.” Ocean acidification is affecting the entire marine environment, causing increasingly dire impacts on marine life and sea food chains.

Since the industrial revolution, the atmospheric concentration of carbon dioxide has increased from 280 to over 400 parts per million due to the burning of fossil fuels such as coal, gas, and oil, along with land use change. The world’s surface ocean is tightly linked with the atmosphere and absorbs huge amounts of carbon dioxide each year. This exchange, in part, helps to regulate the planet’s atmospheric CO₂ concentrations — were it not for ocean uptake of CO₂, atmospheric CO₂ levels would be increasing at an even greater rate than they are now. But, it comes at a cost for the oceans and ocean life; from the smallest, single-celled algae to the largest whales.

Ocean acidification is causing ecosystems and marine biodiversity to change. Rapidly-shifting ocean chemistry has been widely blamed for observed recent damage to coral reef colonies, which negatively impact the marine food chain and fish reproductive processes for the surrounding areas. These changes have the potential to affect both marine life and food security for the entire planet, as most nations get a substantial portion of human food from the sea. Scientists and policy makers are now concerned that our carbon emissions, which are rapidly changing the oceans’ chemistry, will cause a mass extinction within the oceans as a direct result of what we generally think of as “climate change” but whose impacts are substantially broader and far more devastating than many people widely recognize.

While the CO2 that has already been absorbed has helped to moderate the degree of planetary warming we’ve experienced to date, the ocean’s limited capacity to continue absorbing CO₂ from human emissions poses considerable climate “tipping point” risks to humans. Once the ocean capacity to absorb more CO₂ diminishes, more of the carbon dioxide we emit will remain in the atmosphere, further aggravating global warming and evincing a rapid acceleration of the rate at which the climate changes. When that happens, few species will be equipped to adapt to such unprecedented rates of climate change.

It is widely believed that the economic impact of continued ocean acidification to be substantial, especially with the risk of collapse of fisheries around the world. Reducing and eventually eliminating our CO₂ emissions is the only way to minimize long-term, large-scale risks. Reducing the amount of excess carbon dioxide in the oceans through specific activity to draw down and remove the level of excess carbon, will be the only way to begin to restore full health to the ocean.

Click this image to hear Ken Caldeira interviewed by Richard Harris of NPR News.

Science News

We invite you to read more of the original scientific literature widely available about the impacts of ocean acidification.  Here are some of the studies that we’ve found.

Scientists pinpoint how ocean acidification weakens coral skeletons

Woods Hole Oceanographic Institution, January 29, 2018

Summary:  The rising acidity of the oceans threatens coral reefs by making it harder for corals to build their skeletons.  A new study identifies the details of how ocean acidifcation affects coral skeletons, allow scientists to predict more precisely where corals will be more vulnerable.

Declining oxygen in the global ocean and coastal waters

Science Magazine, January 5, 2018

Summary:  As plastic waste pollutes the oceans and fish stocks decline, unseen below the surface another problem grows: deoxygenation. Breitburg et al. review the evidence for the downward trajectory of oxygen levels in increasing areas of the open ocean and coastal waters. Rising nutrient loads coupled with climate change—each resulting from human activities—are changing ocean bio-geochemistry and increasing oxygen consumption. This results in destabilization of sediments and fundamental shifts in the availability of key nutrients. In the short term, some compensatory effects may result in improvements in local fisheries, such as in cases where stocks are squeezed between the surface and elevated oxygen minimum zones. In the longer term, these conditions are unsustainable and may result in ecosystem collapses, which ultimately will cause societal and economic harm.

Ocean acidification means major changes for California mussels

Florida State University, January 5, 2018

Summary:  Accelerating ocean acidifcation could be transforming the fundamental structure of California mussel shells, according to a new report from a Florida State-led team of scientists.  For thousands of years, California mussel shells have shared a relatively uniform mineralogical makeup — long, cylindrical calcite crystals ordered in neat vertical rows with crisp, geometric regularity. But in a study published this week in the journal Global Change Biology, researchers suggest that escalating rates of ocean acidification are shaking up that shell mineralogy on its most basic structural levels.

Landmark global scale study reveals potential future impact of ocean acidification: International research teams takes integrative approach to analysing impact of acidic water on marine snails

University of Plymouth, January 9, 2017

Summary:  Ocean acidification and the extent to which marine species are able to deal with low pH levels in the Earth’s seas, could have a significant influence on shifting the distribution of marine animals in response to climate warming, as reported by ScienceDaily.

Ocean warming and acidification impact on calcareous phytoplankton and reduce its ability to sequester atmospheric carbon dioxide

Universitat Autònoma de Barcelona, July 12, 2016

Summary:  Researchers warn of the negative impacts of rapid ocean warming and ocean acidification on cocolithophores, and consequently in the regulatory processes of atmospheric and ocean concentrations of carbon dioxide, as reported by ScienceDaily.

Acidification affects the ability of bacteria to clean our oceans

Expertsvar, January 12, 2016

Summary:  Marine bacteria are heavily influenced by the ongoing ocean acidification caused by human emissions of carbon dioxide. “It is well known that the acidification of our oceans causes the degradation of coral reefs and disturbs the production of the calcareous shells of important phytoplankton,” says Jarone Pinhassi, professor in marine microbiology at Linnaeus University in Kalmar, Sweden. “However, it is new that also bacteria are affected negatively by ocean acidification.” (ScienceDaily)

Ancient marine algae provides clues of climate change impact on today’s microscopic ovean organisms

University of Southampton, November 27, 2014

Summary:  A study of ancient marine algae has found that climate change affected their growth and skeleton structure, which has potential significance for today’s equivalent microscopic organisms that play an important role in the world’s oceans.  Coccolithophores, a type of marine algae, are prolific in the ocean today and have been for millions of years.  These single-celled plankton produce calcite skeletons that are preserved in seafloor sediments after death.  Although coccolithophores are microscopic, their abundance makes them key contributors to marine ecosystems and the global carbon cycle. The research, published in Nature Communications, examined preserved fossil remains of coccolithophores from a period of climate warming and ocean acidification that occurred around 56 million years ago – the Paleocene Eocene Thermal Maximum (PETM) – and provides a much-needed long-term perspective of coccolithophore response to ocean acidification.

Unshelled abalone and corrupted urchins: development of marine calcifiers in a changing ocean

Maria Byrne, Melanie Ho, Eunice Wong, Natalie A. Soars, Paulina Selvakumaraswamy, Hannah Shepard-Brennand, Symon A. Dworjanyn, andrew R. Davis, December 22, 2010. DOI: 10.1098/lrspv.2010.2404

Summary:  A study of ancient marine algae has found that climate change affected their growth and skeleton structure, which has potential significance for today’s equivalent microscopic organisms that play an important role in the world’s oceans.  Coccolithophores, a type of marine algae, are prolific in the ocean today and have been for millions of years.  These single-celled plankton produce calcite skeletons that are preserved in seafloor sediments after death.  Although coccolithophores are microscopic, their abundance makes them key contributors to marine ecosystems and the global carbon cycle.

Resources:

[Note: Ocean acidification experts: We could use your help. Please consider taking ownership of this page and keeping it updated!]